An Efficient Ru^II–Rh^III–Ru^II Polypyridyl Photocatalyst for Visible‐Light‐Driven Hydrogen Production in Aqueous Solution

Abstract

The development of multicomponent molecular systems for the photocatalytic reduction of water to hydrogen has experienced considerable growth since the end of the 1970s. Recently, with the aim of improving the efficiency of the catalysis, single-component photocatalysts have been developed in which the photosensitizer is chemically coupled to the hydrogen-evolving catalyst in the same molecule through a bridging ligand. Until now, none of these photocatalysts has operated efficiently in pure aqueous solution: a highly desirable medium for energy-conversion applications. Herein, we introduce a new ruthenium-rhodium polypyridyl complex as the first efficient homogeneous photocatalyst for H2 production in water with turnover numbers of several hundred. This study also demonstrates unambiguously that the catalytic performance of such systems linked through a nonconjugated bridge is significantly improved as compared to that of a mixture of the separate components.

Photo-induced redox catalysis for proton reduction to hydrogen with homogeneous molecular systems using rhodium-based catalysts

“…Interestingly, except a recent study by the group of Rau [136] involving a binuclear ruthenium-rhodium linked through a Nheterocyclic-carbene bridging ligand, the two other linked systems involving a rhodium unit as catalyst rely on relatively similar polypyridyl ruthenium-rhodium trinuclear systems that mainly differs from the nature of the link, conjugated for the group of Brewer [70] versus non-conjugated for our group [72].…”

“…Our group very recently reported [72] the first efficient single-component photocatalyst for H 2 evolution in water that associated by a covalent link the [Rh(dmbpy) 2 Cl 2 ] + catalyst (Rh9) to two photoactive [Ru(bpy) 3 ] 2+ units (Fig. 20).…”

“…In association with a sacrificial electron donor, most of them operate in organic medium or in a mixture of aqueous-organic solvents, and only a few have been reported to be active in fully aqueous solution [40,62,[70][71][72]. Some of these linked systems have provided high turnover numbers per catalyst (or photocatalyst) [68] and the most active linked systems so far in water relies on rhodium-based catalyst [72].…”

“…Many linked systems have been reported in literature that combine a Ru, Ir, Re, or Os complex, a porphyrin (Zn, Mg, Al), or an organic dye as the PS with a Pt, Pd, Rh, Co or Fe complex as H 2 -evolving catalyst [11,[27][28][29][30][31][32][33][34][60][61][62][63][64][65][66][67][68][69][70]. In association with a sacrificial electron donor, most of them operate in organic medium or in a mixture of aqueous-organic solvents, and only a few have been reported to be active in fully aqueous solution [40,62,[70][71][72]. Some of these linked systems have provided high turnover numbers per catalyst (or photocatalyst) [68] and the most active linked systems so far in water relies on rhodium-based catalyst [72].…”

Seven‐Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C3v Geometrical Structures

“…[1][2][3] A typical luminescent metal complex is composed of one metal ion and characteristic organic ligands in a three-dimensional structure. The three-dimensional geometries of coordination structures dominate their photochemical and photophysical properties.…”